/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.zookeeper.jmx;

import java.util.Enumeration;

import javax.management.JMException;
import javax.management.MBeanServer;
import javax.management.ObjectName;

import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.apache.log4j.jmx.HierarchyDynamicMBean;
import org.apache.log4j.spi.LoggerRepository;

/**
 * Shared utilities
 */
public class ManagedUtil {
	/**
	 * Register the log4j JMX mbeans. Set environment variable
	 * "zookeeper.jmx.log4j.disable" to true to disable registration.
	 * 
	 * @see http://logging.apache.org/log4j/1.2/apidocs/index.html?org/apache/log4j/jmx/package-summary.html
	 * @throws JMException if registration fails
	 */
	public static void registerLog4jMBeans() throws JMException {
		if (Boolean.getBoolean("zookeeper.jmx.log4j.disable") == true) {
			return;
		}

		MBeanServer mbs = MBeanRegistry.getInstance().getPlatformMBeanServer();

		// Create and Register the top level Log4J MBean
		HierarchyDynamicMBean hdm = new HierarchyDynamicMBean();

		ObjectName mbo = new ObjectName("log4j:hiearchy=default");
		mbs.registerMBean(hdm, mbo);

		// Add the root logger to the Hierarchy MBean
		Logger rootLogger = Logger.getRootLogger();
		hdm.addLoggerMBean(rootLogger.getName());

		// Get each logger from the Log4J Repository and add it to
		// the Hierarchy MBean created above.
		LoggerRepository r = LogManager.getLoggerRepository();
		Enumeration enumer = r.getCurrentLoggers();
		Logger logger = null;

		while (enumer.hasMoreElements()) {
			logger = (Logger) enumer.nextElement();
			hdm.addLoggerMBean(logger.getName());
		}
	}

}
